Gaseous electric discharge device



June 5, 1934. H. EWEST ET AL 1,951,750

GASEOUS ELECTRIC DISCHARGE DEVICE Filed Dec. 15, "1933 INVENTORS latented June 5, 1934- PATENT OFFICE 1,961,150 I GASEOUS ELECTRIC DISCHARGE DEVICE Hans Ewest, Berlin-[dchterfelde-Ost, and Georg Gaidies, Berlin-Pankow, Germany, assignors to General Electric Company, a corporation of New York Application DecemberlS, 1933, Serial No. 702,590 I lin Germany December 31, 1932' 3 Claims.

The present invention relates to gaseous electric discharge devices generally and more particularly the invention relates to such devices useful as light sources in television work or the like.

Sodium lamps having thermionic electrodes and a gas filling are useful in television work because of the high efliciency of such lamps and the high intensity of the light emitted thereby. We have observed that sodium lamp devices do not respond instantaneously to the oscillations of the current supply of the lamp which causes a blurring of the picture reproduced by the television apparatus.

The object of the present invention is to pro- 15 duce a lamp which responds instantaneously to the oscillations of the current supply thereof. Still further objects and advantages attachingto the device and to its use and operation will'be apparent to those-skilled in the art from the following. particular description.

We have discovered that the addition of a small amount of mercury, up to about to the sodium in a rare gas filled sodium lamp having ther- M mionic electrodes makes such lamps instantaneously responsive to the oscillations of the current supp y of the lamp. We find it desirable that the quantity of mercury in the lamp be such that substantially all the mercury is in a vaporous condition at the operating temperature of the lamp. Where the operating temperature of the lamp is 400 C. or higher the mercury can be 1% or less of the sodium. For operating temperatures of approximately 300 C. an addition of 4 to 5% of mercury to the sodium is desirable. In

any case it is preferable that the quantity of mercury be such that the sodium spectrum predominates in the spectrum of the light emitted by the lamp for under these conditions the high efiiciency and high intensity light emission characteris- 49 tic or sodium lamps are retained.

In the drawing accompanying and forming part or this specification an embodiment of the invention is shown in a side elevational view, but as such illustration is primarily for purposes of disclosure it-will be understood of course that numerous changes in the form and details of the device and in its use and operation may be made by those skilled in the art without departure 50 from the broad spirit and scope of the invention. gaseous electric discharge device comprises a container 1 having thermionic electrodes 2' and 3 sealed therein. Said electrodes 2 and 3-c0nsist of a r'odot electronemitting material, such as barium oxide, ended by a filamentary metal Referring to the drawing the new and novel heating coil, such as a tungsten filament. Said container 1 has a gaseous atmosphere therein comprising a starting gas, such as argon or neon, ora mixture of such gases; a diflicultly vaporizable material, such as sodium, indicated at 4, and

a quantity of. mercury, indicated at 5. The

rial is in a vaporous condition during the operation of the lamp and that the mercury should not be in excess of about 10% of the sodium in any case in order that the lamp retain the high emciency and intense light emission characteristics oi a sodium lamp.

While we have shown and described the mercury as being introduced into the container 1 separately from the sodium it will be understood, of course. that we contemplate that the mercury can be introduced into the lamp in the form of sodium amalgam the above proportions being observed.

The container 1 is maintained at the high temperature required for an effective vapor pressure of the diflicultly vaporizable material during the operation of the device by the high current density discharge therein made possible by the use of thermionic electrodes 2 and 3. I When desired, the container 1 is provided with a heat conservator to assist in maintaining said container 1 at a high temperature during the operation of the device. A suitable heat conservator is a double walled, evacuated jacket, or a single walled jacket having a gas of poor heat conductivity therein enclosing said container 1. When desired, the container 1 has baflles interposed between the electrodes 2 and 3 and the stem parts.-

of said container 1 completely closing cit said stem parts from the other parts of said container 1 to protect said stem parts from the eifects of the metal vapor in the lamp device. Itwill be understood, ct course, that the shape of the container l can be changed to suit the needs of the service to which the lamp is to be put, for example, a bulb shaped container is desired in many applications of the lamp.

What we claim as new and desire to secure by Letters Patent 0! theUnited States is:

'1. An electric discharge device comprising a container, electrodes sealed therein, a gaseous atmospheretherein comprising a starting gas, a dimcultly vaporizable material and mercury, the

mercury being approximately 10% of the difli-" 3. An electric discharge device comprising a container, electrodes sealed therein, a gaseous atmosphere therein comprising a starting gas, sodium and mercury, the mercury being approximately 1 to 10% of the sodium.

HANS EWEST. GEORG GAIDIES. 

